【摘要】 陶瓷被广泛用作催化燃烧的催化剂载体。为及时将反应热导出,避免催化剂烧结、失活,需提高陶瓷导热能力。针对通过填充高导热性的金属或无机填料的方法制成的陶瓷复合导热材料,引入二维九速度不可压格子多相Lattice-Boltzmann模型,对构造的5种规则填充形状(圆形、正八边形、正六边形、正四边形和正三角形)的陶瓷基复合材料进行了完整的二维导热过程的数值分析。结果表明,在相同的填料和填充体积分数下,三角形填充的复合材料有效导热系数最大,填充形状愈趋近圆形则有效导热系数越小。同时模拟了各填充形状下,填充材料与基体材料的导热系数之比kp/km对复合材料有效导热系数的影响。研究结果表明,孤立的导热填料对于复合材料导热系数的提高作用是有限的,当kp/km增大到一定程度,有效导热系数不再明显增加。更多还原

【Abstract】 Ceramic material is widely used as the catalyst carrier of catalytic combustion.To avoid the deactivation of catalyst,it is important to improve the heat transfer capacity of carrier so as to conduct the heat of reaction in time.A two-dimensional nine-speed(D2Q9)lattice Boltzmann incompressible thermal model is introduced to carry out the numerical analysis of two-dimensional heat transfer in ceramic matrix composite filled with high heat conductivity metal or inorganic filler.Five regular shapes(circle,regular octagon,regular hexagon,square and regular triangle)are investigated.The results indicate that at the same filling fraction,triangular filler has the best performance to increase composite′s effective thermal conductivity;the more circular the shape is,the lower the effective thermal conductivity become.The relationship between the effective thermal conductivity kcand the thermal conductivity ratio of the filler to the matrix kp/kmwas also obtained.The results show that the effect of isolated filler on enhancing heat conduction capacity of composite is limited.When kp/kmincreases to a certain degree,the effective thermal conductivity will not increase significantly any more.更多还原